The present invention relates to a motor-driven film winder for use with a camera.
For making successive exposures rapidly on a camera, a motor-driven film winder is usually used in combination with the camera for automatically winding or transporting the film. Such a motor-driven film winder is capable of transporting film frames successively at a high rate, such as several frames per second, as long as the shutter release button is pressed. Therefore, it would be difficult for even a skilled photographer to control the number of exposures to be made simply by operating the shutter release button. More or less frames than desired would frequently be exposed in the motor-driven film transport mode. Accordingly, there have been demands for a motor-driven film winder capable of allowing the user to set a desired number of exposures to be made.
The motor-driven film winder with such an exposure number setting capability should preferably be designed to incorporate some means for indicating the number of any remaining frames available for exposure when the motor drive exposure sequence would be interrupted for some reasons such as an unexpected change of the object being photographed.
Motor-driven film winders are also desired to enable the camera to make intermittent exposures at prescribed time intervals so that various continuously changing phenomena such as the growth and condition of animals and plants can be recorded at regular intervals. Another use of the intermittent or interval photographing system is to automatically take pictures of places requiring continuous watching, such as areas around entrances, exits, teller's cages, vaults of banks or other financial institutions. Should a crime such as bank robbery be committed in the bank or financial facility, some pictures taken by the interval photographing system may be used as evidence of the crime or to identify the criminal or criminals involved. Since the interval photographing system is automatically operated and not usually attended by anybody during operation, it uses an elongate strip of film to take pictures successively for a long period of time. However, some areas only need to be photographed intermittently only during the daytime or for a prescribed period of time.
The conventional motor-driven film winders capable of interval or intermittent picture-taking operation have failed to stop the interval photographing process after a predetermined number of frames have been exposed or a preset time has elapsed. Therefore, many pictures have been taken intermittently under bad conditions as during the night or with inappropriate exposure settings or of unnecessary objects, with the result that some film frames has been wasted.
One solution to the above problems would be to use a proper accessory in combination with the camera. However, the camera with such an accessory would be poor in portability and undesirable economically.